Hydrogen Fluoride in High-Mass Star-forming Regions

Hydrogen fluoride has been established to be an excellent tracer of molecular hydrogen in diffuse clouds. In denser environments, however, the HF abundance has been shown to be approximately two orders of magnitude lower. We present Herschel/HIFI observations of HF J=1-0 toward two high-mass star formation sites, NGC6334 I and AFGL 2591. In NGC6334 I the HF line is seen in absorption in foreground clouds and the source itself, while in AFGL 2591 HF is partially in emission. We find an HF abundance with respect to H2 of 1.5e-8 in the diffuse foreground clouds, whereas in the denser parts of NGC6334 I, we derive a lower limit on the HF abundance of 5e-10. Lower HF abundances in dense clouds are most likely caused by freeze out of HF molecules onto dust grains in high-density gas. In AFGL 2591, the view of the hot core is obstructed by absorption in the massive outflow, in which HF is also very abundant 3.6e-8) due to the desorption by sputtering. These observations provide further evidence that the chemistry of interstellar fluorine is controlled by freeze out onto gas grains.Comment: accepted in Ap

Maldi-Tof mass spectometry as a routine technique for identification of typical and atypical mycobacteria in the Laboratory of Clinical Microbiology

Introducción y Objetivo: Del género Mycobacterium se han descrito más de 120 especies de micobacterias diferentes de crecimiento lento y rápido. Estos microorganismos producen una importante morbilidad en humanos, incluyendo infecciones de tipo pulmonar, en la piel y tejidos blandos y enfermedad diseminada siendo el diagnóstico rápido y preciso es de gran importancia. Material y Métodos: La población de estudio de nuestro trabajo fueron 75 aislados de micobacterias procedentes de cultivo en medio sólido Lowenstein-Jensen. El diagnóstico fue realizado mediante técnicas moleculares de PCR e hibridación inversa: GenoType Mycobacterium CM y GenoType Mycobacterium AS. De forma paralela las cepas se identificaron mediante espectrometría de masas MALDITOF MS (Matrix-Assisted Laser Desorption Ionization– Time of Flight Mass Spectrometry). Resultados: La concordancia global de resultados entre la identificación realizada mediante PCR y la tecnología MALDI-TOF fue del 97%, con un coeficiente kappa de correlación de 0.929 (correlación excelente entre 0.081-1.0). Conclusiones: Nuestros resultados indican que es bastante factible incorporar MALDI-TOF MS para la identificación rutinaria de micobacterias en el flujo de trabajo del laboratorio de microbiología clínica.Introduction and aim: in the Mycobacterium genus have been described more than 120 species of Mycobacteria other than growth slow and fast. These microorganisms produce significant morbidity in humans, including type pulmonary infections, skin and soft tissues and disseminated disease being the rapid and precise is of great importance. Material and methods: the study population of our work were 75 isolated Mycobacteria from cultivation in solid Lowenstein-Jensen medium. The diagnosis was made by molecular techniques of PCR and reverse hybridization: GenoType Mycobacterium CM and GenoType Mycobacterium AS. Parallel strains were identified by mass spectrometry MALDITOF MS (Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry). Results: The overall agreement of results between the identification made by PCR and MALDI-TOF technology was 97, with a coefficient of correlation of 0.929 kappa (excellent correlation between 0.081-1.0). Conclusions: Our results indicate that it is quite feasible to incorporate MALDI-TOF MS for routine identification of Mycobacteria in the clinical microbiology laboratory workflow

Carbapenemase detection in Pseudomonas aeruginosa by MALDI-TOF MS mass spectrometry

Introducción: Las bacterias gramnegativas, especialmente Pseudomonas, presentan con frecuencia resistencia a múltiples antibióticos incluyendo carbapenemes. La resistencia a carbapanemes se ha incrementado en los últimos años causada por alteraciones de membrana o por la producción de carbapenemasas. Objetivo: Valorar la utilización de la espectrometría de masas MALDI-TOF MS® para la detección de carbapenemasas clase A o B en Pseudomonas aeruginosa. Material y métodos: Partiendo de 12 aislados de Pseudomonas aeruginosa productoras de carbapenemasas clase A o B identificados mediante método de difusión disco-placa, tipificadas usando los discos: meropenem 10µg, meropenem 10µg + ácido borónico, meropenem 10µg + cloxacilina y meropenem 10µg + ácido dipicolínico (Rosco Diagnostica), hemos analizado posibles picos de hidrólisis del meropenem tras la acción de las carbapenemasas mediante espectrometría de masas MALDI-TOF MS®. Como controles negativos se utilizaron 25 cepas de Pseudomonas aeruginosa sensibles a meropenem y 8 cepas de Pseudomonas aeruginosa con impermeabilidad de membrana, no detectables mediante la metodología utilizada. Resultados: De las 12 cepas productoras de carbapenemasas clase A o B, (2/12 clase A, 10/12 clase B), la técnica de espectrometría de masas MALDI-TOF MS® detectó picos de degradación del antibiótico en estudio correspondientes a la presencia de carbapenemasas en 11/12 casos (94.4%). En las cepas usadas como controles negativos, la espectrometría de masas MALDI-TOF MS® indicó la ausencia de carbapenemasas clase A o B en 31/33 (93.9%) casos. Conclusión: La espectrometría de masas MALDI-TOF MS® puede ser una herramienta útil para la confirmación de carbapenemasas clase A y B en Pseudomonas aeruginosa.Introduction: Gram-negative bacteria especially Pseudomonas are resistance to multiple antibiotics including carbapenems. Carbapanemes resistance has increased in recent years caused by alterations of membrane or the production of carbapenemases. Objective: Assess the use of MALDI-TOF MS® mass spectrometry for the detection of carbapenemases class A or B in Pseudomonas aeruginosa. Material and methods: From isolated from Pseudomonas aeruginosa producing carbapenemases 12 class A or B identified by diffusion method disco-plate, classified using disks: meropenem 10μg, meropenem 10μg + boronic acid, meropenem 10μg + cloxacillin and meropenem 10μg + acid dipicolinic (Rosco Diagnostica), we analyzed possible hydrolysis of meropenem peaks after the action of the carbapenemases by MALDI-TOF MS® mass spectrometry. As negative controls were used 25 strains of Pseudomonas aeruginosa sensitive to meropenem and 8 strains of Pseudomonas aeruginosa with waterproof membrane, not detectable by the methodology used. Results: Of the 12 strains producing carbapenemases class A or B, (2/12 class A, 10/12 class B), MALDI-TOF MS® mass spectrometry technique detected peaks of degradation of the antibiotic in study to the presence of carbapenemases in 11/12 cases (94.4%). The strains used as controls negative, MALDI-TOF MS® mass spectrometry indicated the absence of carbapenemases class A or B at 31/33 cases (93.9%). Conclusion: MALDI-TOF MS® mass spectrometry can be a useful tool for the confirmation of carbapenemases class A and B in Pseudomonas aeruginosa

Herschel observations of EXtraordinary Sources: Analysis of the full Herschel/HIFI molecular line survey of Sagittarius B2(N)

A sensitive broadband molecular line survey of the Sagittarius B2(N) star-forming region has been obtained with the HIFI instrument on the Herschel Space Observatory, offering the first high-spectral resolution look at this well-studied source in a wavelength region largely inaccessible from the ground (625-157 um). From the roughly 8,000 spectral features in the survey, a total of 72 isotopologues arising from 44 different molecules have been identified, ranging from light hydrides to complex organics, and arising from a variety of environments from cold and diffuse to hot and dense gas. We present an LTE model to the spectral signatures of each molecule, constraining the source sizes for hot core species with complementary SMA interferometric observations, and assuming that molecules with related functional group composition are cospatial. For each molecule, a single model is given to fit all of the emission and absorption features of that species across the entire 480-1910 GHz spectral range, accounting for multiple temperature and velocity components when needed to describe the spectrum. As with other HIFI surveys toward massive star forming regions, methanol is found to contribute more integrated line intensity to the spectrum than any other species. We discuss the molecular abundances derived for the hot core, where the local thermodynamic equilibrium approximation is generally found to describe the spectrum well, in comparison to abundances derived for the same molecules in the Orion KL region from a similar HIFI survey.Comment: Accepted to ApJ. 64 pages, 14 figures. Truncated abstrac

Herschel observations of interstellar chloronium

Using the Herschel Space Observatory's Heterodyne Instrument for the Far-Infrared (HIFI), we have observed para-chloronium (H2Cl+) toward six sources in the Galaxy. We detected interstellar chloronium absorption in foreground molecular clouds along the sight-lines to the bright submillimeter continuum sources Sgr A (+50 km/s cloud) and W31C. Both the para-H2-35Cl+ and para-H2-37Cl+ isotopologues were detected, through observations of their 1(11)-0(00) transitions at rest frequencies of 485.42 and 484.23 GHz, respectively. For an assumed ortho-to-para ratio of 3, the observed optical depths imply that chloronium accounts for ~ 4 - 12% of chlorine nuclei in the gas phase. We detected interstellar chloronium emission from two sources in the Orion Molecular Cloud 1: the Orion Bar photodissociation region and the Orion South condensation. For an assumed ortho-to-para ratio of 3 for chloronium, the observed emission line fluxes imply total beam-averaged column densities of ~ 2.0E+13 cm-2 and ~ 1.2E+13 cm-2, respectively, for chloronium in these two sources. We obtained upper limits on the para-H2-35Cl+ line strengths toward H2 Peak 1 in the Orion Molecular cloud and toward the massive young star AFGL 2591. The chloronium abundances inferred in this study are typically at least a factor ~10 larger than the predictions of steady-state theoretical models for the chemistry of interstellar molecules containing chlorine. Several explanations for this discrepancy were investigated, but none has proven satisfactory, and thus the large observed abundances of chloronium remain puzzling.Comment: Accepted for publication in the Astrophysical Journa

A Swedish heterodyne facility instrument for the APEX telescope

In March 2008, the APEX facility instrument was installed on the telescope at the site of Lliano Chajnantor in northern Chile. The main objective of the paper is to introduce the new instrument to the radio astronomical community. It describes the hardware configuration and presents some initial results from the on-sky commissioning. The heterodyne instrument covers frequencies between 211 GHz and 1390 GHz divided into four bands. The first three bands are sideband-separating mixers operating in a single sideband mode and based on superconductor-insulator-superconductor (SIS) tunnel junctions. The fourth band is a hot-electron bolometer, waveguide balanced mixer. All bands are integrated in a closedcycle temperature-stabilized cryostat and are cooled to 4 K. We present results from noise temperature, sideband separation ratios, beam, and stability measurements performed on the telescope as a part of the receiver technical commissioning. Examples of broad extragalactic lines are also included

Sepsityper® for rapid identification of microorganisms from positive blood cultures

Nuestro estudio ha evaluado las ventajas de la utilización del kit Sepsityper® para la identificación rápida de microorganismos a partir de hemocultivos positivos, acompañado de la tecnología de espectrometría de masas MALDITOF MS®, en comparación con los métodos tradicionales empleados para el diagnóstico de bacteriemia. Para la identificación del microorganismo en 379 hemocultivos positivos en el Departamento de Microbiología del Hospital Universitario San Cecilio, se aplicó la espectrometría de masas MALDITOF MS® utilizando el sistema Sepsityper® (Bruker) y se comparó con la identificación mediante métodos convencionales (Wider, Vitek II, Api). La correlación de resultados de los dos esquemas diagnósticos fue determinada estadísticamente por el coeficiente de correlación kappa. La distribución de los aislamientos fue de un 24,7 % de Bacilos Gram negativos (BGN) y 75,3 % de microorganismos Cocos Gram positivos (CGP). La concordancia global de resultados fue del 95,8 % en la especie (k = 0,928) y del 98,7 % en el género (k = 0,977), siendo el porcentaje de identificaciones fallidas del 1,3%. Para BGN hubo una concordancia de resultados del 95,2 % (k = 0,928, especie), y 100 % (k = 1, género). Respecto a los CGP, la concordancia fue del 98,2 % en género (k = 0,931), y del 82,5 % (k = 0,627) a nivel de especie. En nuestra experiencia se ha observado una ganancia de al menos 13–23h en la identificación a nivel de especie. La utilización del kit Sepsityper® para la identificación rápida de microorganismos a partir de hemocultivos positivos, acompañado de MALDITOF MS®, muestra una excelente correlación respecto a la identificación realizada a través de la metodología convencional, con una importante disminución del tiempo hasta la identificación.Our study has evaluated the advantages of using Sepsityper® kit for a fast identification of microorganisms from positive blood cultures, along with the mass spectrometry technology MALDITOF-MS®, compared to traditional methods used for diagnosis of bacteremia. To identify the microorganism isolated from the 379 positive blood cultures (BC +) the Department of Microbiology, University Hospital San Cecilio, MALDITOFMS® mass spectrometry along with Sepsityper® (Bruker) were applied and it was compared to the conventional methods for the identification of this organism. The correlation of results between these two diagnostic schemes was statistically determined by kappa correlation coefficient. The distribution of the isolates was 24.7% for Gram negative bacilli (GNB) and 75.3% for Gram-positive cocci (GPC). The overall concordance of results was 95.8% within the species (k = 0.928) and 98.7% within the genus (k = 0.977), with a failed-identification percentage of 1.3%. For GNB there was a concordance of results of 95.2% (k = 0.928, species), and 100% (k = 1, genus). Regarding the GPC, the concordance was 98.2% within the genus (k = 0.931), and 82.5% (k = 0.627) at the species level. According to our experience there was a gain of at least 13-23 hours in the identification of the microorganisms at the species level. The use of Sepsityper® kit for the rapid identification of microorganisms from positive blood cultures, along with MALDITOF-MS®, show an excellent correlation compared to identification made by the conventional methods, with a significant reduction in time until identification